For example, there have been power devices to perform charge/discharge operation of a secondary cell, storing of charges to a capacitor or the like and discharging thereof, or power supplying to electrical equipment and power consuming for performing equipment operation. In the following description, a power device to perform power supplying and power consuming as described above is denoted as a charging/discharging device. Further, an object on which the charging/discharging device performs power supplying and power consuming is denoted as a charge/discharge member.
For example, when the abovementioned charging/discharging device is used as a charging/discharging device for a secondary cell, the charging/discharging device repeatedly performs charge operation to apply a charging voltage to a secondary cell for a predetermined time and discharge operation to absorb discharge electric power from the charged secondary cell for a predetermined time.
Thus, when the abovementioned charging/discharging device is used as a power device to cause a secondary cell to perform charge/discharge operation, the charging/discharging device can be used, for example, as a conditioning device to activate cell performance of a secondary cell, an aging device to repeatedly perform charge/discharge operation until a secondary cell obtains predetermined cell performance, a charge/discharge testing device for a secondary cell, a cycle testing device to examine temporal charge/discharge cycle performance of a secondary cell, and the like (see Patent Document 1 and Patent Document 2).
Here, operation in a case that a charging/discharging device is used as a conditioning device for a secondary cell is briefly described as an example using FIGS. 2 and 3. FIGS. 2 and 3 illustrate a case that the charging/discharging device is used as a conditioning device for a secondary cell which is a later-mentioned quantum cell.
As illustrated in FIG. 2, in a charging/discharging device 100A, a power source 103 outputs drive current to a power amplifier 101 and the power amplifier 101 applies a voltage having a predetermined waveform to a secondary cell 104 based on the drive current from the power source 103.
As illustrated in FIG. 3(A), for charging the secondary cell 104 being a quantum cell, the power amplifier 101 applies a voltage V1 higher than a charging voltage V2 instantly for a time T1 to activate the secondary cell 104, and then, applies the charging voltage V2 to the secondary cell 104 for a predetermined time T2. Further, for discharging the secondary cell 104, the power amplifier 101 applies a voltage V3 lower than a discharging voltage V4 instantly for a time T3 to activate the secondary cell 104, and then applies the charging voltage V4 to the secondary cell 104 for a predetermined time T4. In charge/discharge operation for the secondary cell 104, the charging/discharging device 100A repeatedly performs operation illustrated in FIG. 3(A).
Further, operation in a case that a charging/discharging device is used as a charge/discharge testing device for a secondary cell is briefly described as an example using FIG. 4.
The charging/discharging device illustrated in FIG. 4 adopts a constant-current constant-voltage (CC-CV) charging method for charging a secondary cell. In the CC-CV charging method, charging is started with constant current (CC) to avoid overvoltage, and is switched to a constant voltage (CV) when a voltage of the secondary cell reaches a predetermined voltage. Here, discharging is performed with constant current (CC) when the charging/discharging device absorbs discharge of the secondary cell.
Here, the charging/discharging method of a secondary cell is not limited to the CC-CV charging method and the CC discharging method in FIG. 4. Aside from the CC-CV charging method, it is also possible to adopt a CC charging method, a CV charging method, or the like as the charging method. Further, aside from the CC discharging method, it is also possible to adopt a discharging method with resistance load (R discharging method), or the like as the discharging method.
Further, as described above, the charging/discharging device can be used as an aging device for a secondary cell, a cycle testing device for a secondary cell, and the like.
Further, in a case that a plurality of secondary cells are caused to perform charge/discharge operation (e.g., conditioning) concurrently in parallel, as illustrated in FIG. 5, a charging/discharging device 100B includes a required number (N pieces in FIG. 5) of power amplifiers 101 and each power amplifier 101 performs charge/discharge operation on a corresponding secondary cell 104 concurrently in parallel.